Simply White has a creamy undertone. I like the grays....like Edgecomb Gray and Winterwood (both taupe/gray). The greener grays like Old Prairie are so pretty too with the creamy white. I think it might be good to see if you have a dominant secondary color that you love....to go with your black/white theme. Do you love a jewel tone as a splash of color (red, yellow, lime green), or do you prefer something more understated like a gray, soft sage or soft blue as an accent? Once you look at a few pictures and see the secondary colors you are attracted to, I think you can start narrowing your decision. In addition, if the floorplan is open, what colors are in the adjacent room--is your couch brown or red? That can tell you something too. I love reading the postings by this woman. She has so many good points and interesting pics that illustrate her colour theories. http://colourmehappyblog.blogspot.com/ Here is a link that might be useful: Colour

You're correct that the slightest difference in whites sets a tone for the home. I think the undertone of your home on the exterior should match somewhat with the interior. Does your interior carry warm undertones? If so I would choose a trim that reflects that. Personally, I like the hale navy color, but I tend to favor paint schemes with more of a cool undertone.

BM Chamois is a warmer white with some yellow undertones, but the current trim color looks fine to be next to the cabinets so if it's close and you're fine with it I say stick with it. Really unless you use the same color as the cabinets it won't be an exact match. Can you paint a sample of the Chamois and hold it against the cabinets to see the contrast? IMO since you have the bright white cabinets and grey soapstone I'd play it safe and go for a cooler white. BM chantilly lace or BM super white would work.

IMO Oxford White is a nice crisp white next to Hale Navy and just use paint no grasscloth.